KEYPADS & DECODING

A simple 4x3 keyboard that allows data entry into bus based systems. Flowcode macros for driving this E-block are available.

3. Single-Wire Keypad Interface by Design Ideas

Occupying only one free I/O pin, this circuit communicates with a microcontroller by generating a single pulse each time someone presses a key. The pulse's width is proportional to the number of the pressed key, and the microcontroller identifies the pressed key by measuring the pulse's width.

4. Keypad Switch — Comfile Technology

2 pages.

5. Keypad Decoding

This Freescale Semiconductor application note demonstrates the use of a matrix keypad including wakeup from stop mode with HC05 J and K series microcontrollers. The MC68HC705J1A is used as an example.

6. Standard Keypads AK-304-FM

1 page.

7. Standard Keypads AK-XXXX

2 pages.

8. Microchip PIC Controlled HD44780 LCD and 3x4 Matrix Keypad

This article provides fundamental information on how to integrate the HD44780 controlled LCD display and matrix keypad with Microchip’s popular 16F877/A. This project can be further improved for numerous applications such as security door lock system and others requiring a hardware interface to input and verify pass keys.

9. Piezo Keypad

Schurter Electronic Components offers a piezo keypad that provides input systems impervious to all kinds of dirt and fluids. Keypads are particularly suitable for use in outdoor applications.